Patent GB-786831-A (GB)
Title: Improvements in or relating to telegraph printers
Inventor: HOWARD BERNARD
IPC: H04L17/26
Filed: 1955-12-09
Abstract: 786,831. Printing-telegraph receivers. TELEPRINTER CORPORATION. Dec. 9, 1955, No. 35498/55. Class 40 (3). [Also in Group XVI] In a printing telegraph receiver having a cable or flexible member for moving a type-carrier to select a character to be printed and a ratchet- and-pawl mechanism for effecting step-by-step movement of the type-carrier across the paper, the cable member comprises two parts used respectively for the character selection and the step-by-step feed and connected by a pulley, the first part being connected to the pulley and the second part being trained around the pulley and being connected at one end to the typecarrier and at the other end to the ratchet-andpawl mechanism which takes up the cable stepby-step. In the arrangement described, the characters are arranged in eight circumferentially disposed rows, each having eight selectable positions, the lower and upper case characters being disposed in opposite halves of the generally cylindrical type-carrier. The axial and rotational positions of the type-carrier are primarily determined by three and two signal elements respectively of a five-unit code and the rotational selection of the appropriate half of the typecarrier is determined by a member operated in response to the code combination representative of the letter shift or figure shift condition. The cable 124 controlling the axial selective movement of the type-carrier 84 is connected to an adjustable fixed support 126 and passes around pulleys 118, 120, 122 connected to solenoids 134, 138, 142 and over a pulley 128 in a frame 132 to a fixed point 130. The solenoids 134, 138, 142 which are operated by coils 136, 140 and 144, have linear movements in the ratio 4 : 2 : 1 and the aggregate movement applied to the frame 132 is transmitted to the carrier 84 by a cable 92 which passes over pulleys 94, 96, 100 to a drum 102 operated by the ratchet-andpawl mechanism. The type-carrier 84 is also connected by a cable 86 to a spring drum 90 which restores the carrier to the initial position when the ratchet mechanism is released. The rotary movement of the carrier 84 is effected by a cable 146, Fig. 6, passing from a fixed support 154 over pulleys 148, 150 operated by solenoids 156, 158 and a pulley 152 controlled by the caseshift signals to a pulley 164 and to a drum 166 connected to a hollow shaft 168 with which the type-carrier 84 has a splined connection. The solenoids 136, 140, 144, 156, 158 are controlled directly from the perforations 38 of a tape 36, Fig. 9, which is stepped by a ratchet 332 controlled by a pawl 334 operated by a cam 336 on the shaft 336 of a motor 338 which also rotates an arm 340 over a sector 342 connecting a battery 346 to the brushes and subsequently over a segment 344 controlling the circuit of the printing magnet 116. The printing hammer 192 which is mounted on a cable 262 and is traversed with the type-carrier 84, is actuated by a printer bar 228 extending across the platen and connected by arms 238 to a lever 108 mounted on a shaft 110 and linked at 112 to the solenoid 114 operated by the coil 116 energized to effect the printing operation. When the solenoid 116 is energized, the lever 108 is rocked to effect the printing operation and the pawl 106 is moved downwards to engage the next tooth 104 on the drum 102. The return of the printing bar 228 under the action of its springs 230 rocks the lever 108 upwardly so that the pawl 106 steps the drum 102 and moves the type-carrier 84 one step to the right. The cable 262 carrying the printing hammer 192 is connected at one end to a drum 272 rotated with the drum 102 and at the other end is attached to a spring drum 266. Ink-ribbon feed. The ink-ribbon 248 is fed from a drum 244 and passes over a guide roller 250 and a feed roller 252 having a gear-wheel 276 driven from a gear 274 on the drum 266 through a one-way clutch so that the ribbon is fed a distance equal to the width of the sheet during the return movement of the carrier 84 and the printing hammer 192. Arrangement for control of functions. A brush member 280 connected to the cable 124 and supported on a rod 282 has a contact member 292 selectively engaging contacts 286, 288, 290 in response to three signal elements of the five-unit code and a further brush 300, Fig. 6, selectively engaging contacts 308, 310, 312 in response to the remaining two elements of the code combination. The engagement of the brushes 280, 300 with selected contacts completes the circuit of magnets controlling the various functions, such as carriage-return, linespacing, case shift, spacing, &c. Line-spacing. The printing sheet 184 is passed over surface 186 and between the printing hammer 192 and type-carrier 84 to a feed roller 182 having a pressure roller 190 and mounted on the shaft of a ratchet-wheel 194 having a pawl 196 on a plate 198 connected through links 202, 204, 206 to a solenoid 216 operated by the engagement of brushes 280, 300 with contacts 286, 310 respectively in response to the line-feed signal. Case-shift operation. For the printing of upper case characters, the figure-shift combination causes brushes 280, 300 to engage contacts 290, 312 energizing magnet 160 which locks up over contacts 350 and operates the pulley 152 to rotate the type-carrier 84 through half a revolution. The operation of the magnet 160 opens contacts 348 so that the printing operation is suppressed in response to the figuresshift signal. The reception of the letters-shift signal causes brushes 280, 300 to engage contacts 292, 312 operating relay 376 which opens contacts 374 so that solenoid 160 is de-energized. The opening of lower contacts 348 suppresses the printing action. Carriage-return. When the brushes 280, 300 engage contacts 288, 308 respectively, the solenoid 316 is energized and through links 318, 320, Fig. 6, rocks the shaft 176 and the lever 174, Fig. 2, so that the feed pawl 106 and retaining pawl 178 are both moved out of engagement with the teeth 104 of the drum 102 allowing the carrier 84 to move to the left under the action of the drum 90. At the same time the hammer 192 is moved to the left by the spring drum 266. Contacts 324 open the circuit of the printing magnet 116 and the solenoid 316 remains energized over contacts 322 and normally closed contacts 354 which are opened when the type-carriage 84 returns to its initial position. If the carriage return signal is not received, the movement of the carrier 84 to the right closes contacts 356 so that solenoid 316 is energized to effect the carriage-return operation.